Hitherto, many reports have been made on transition metal complexes utilizable in organic synthesis reactions, for example, transition metal complex catalysts for use in enantioselective synthesis reactions such as enantioselective hydrogenation reaction, enantioselective isomerization reaction, and enantioselective silylation reaction. Among such transition metal complexes, most of the complexes in which optically active tertiary phosphine compounds are coordinated to transition metals such as ruthenium rhodium, and palladium show excellent efficiency when used as catalysts in enantioselective synthesis reactions. For the purpose of further enhancing the efficiency of this kind of catalysts, a large number of phosphine compounds having special structures have been developed so far [see Kagaku Sosetsu (The Elements of Chemistry) 32, "Chemistry of Organometallic Complexes" pp. 237-238 (1982), edited by The Chemical Society of Japan]. 2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl (hereinafter referred to as "BINAP") is one of the phosphine compounds especially useful as a ligand, and a rhodium complex and a ruthenium complex each containing BINAP as a ligand have been reported in JP-A-55-61937 and JP-A-61-6390, respectively. (The term "JP-A" as used herein means an "unexamined published Japanese patent application".) It has also been reported that a rhodium complex (JP-A-60-199898) and a ruthenium complex (JP-A-61-63690) each containing 2,2'-bis[di-(p-tolyl)phosphino]-1,1'-binaphthyl (hereinafter referred to as "p-T-BINAP") as a ligand give good results when used in enantioselective hydrogenation reaction and enantioselective isomerization reaction. It has further been reported that the enantioselective hydrogenation reaction of nerol using as a catalyst a rhodium complex containing 2,2'-bis(dicyclohexylphosphino)-1,1' -binaphthyl (hereinafter referred to as "CyBINAP") as a ligand yields citronellol having an optical purity of 66% ee [S. Inoue et al., Chemistry Letters, pp. 1007-1008 (1985)].
As described above, a large number of special phosphine compounds have been developed in order to provide complexes which show higher catalytic efficiency when used in enantioselective synthesis reactions. However, there are cases where according to the kind of the reaction to be conducted or to the reaction substrate therefor, those complexes are still insufficient in selectivity, conversion, durability, and other performance. It has, therefore, been desired to develop a novel phosphine compound which gives complexes having significantly improved catalytic efficiency as compared with conventional catalysts.